I'm betting this is heat related but opinions would be nice. My car was fairly hot (in Canada so gauge was reading over 125) as giving lots of rides back-to-back. Normally my sessions are 20min with a good 30min cool-down but today I went pretty hard for over an hour just pulling in to switch passengers (I always did do a cool-down lap). Towards the end of the day when I wanted to accelerate around 6000rpm my car would cut-out. It was like I was hitting the rev-limiter. After a few seconds it would come back. No light on dash.
Another instructor who's car runs hot due to mods said his does this when it's getting too hot before the warning lights come into play.

I don't know if this is an engine protection feature. I would be worried about the high temperature though. When I drive on the Nurburgring, even 5 consecutive laps on a hot summer day, the oil temp never gets above 115 C. Any mods?